Quick Disconnect Coupler

This invention relates to quick disconnect pipe couplers and more particularly to a quick disconnect coupler for locking a marine loading arm to a tanker vessel.

In loading or unloading crude oil, liquified natural gas, or other liquified petroleum products, chemicals or the like, between a tanker vessel and shore installations, it is common practice to use special loading arms by which a segmented pipe connection to the shore installation can be maneuvered into position to connect to pipes on the vessel communicating with the tanks. Generally the moving end of the segmented pipe supported by the loading arm is provided with a coupling device which allows the coupler to attach itself to the flanged end of the pipe on the vessel in a manner to form a fluid-tight joint. Preferably this coupler is hydraulically or electrically operated from a remote location. Since the floating vessel may be moving during the coupling operation, or because the coupler must be easily disconnected in an emergency, a quick disconnect coupling system is highly desirable. A number of such couplers have been developed in the prior art, such as shown, for example, in U.S. Pat. Nos. 3,558,161, and 3,865,409. Such couplings typically involve a plurality of clamping assemblies having jaws which are movable in and out of engagement with the flanged end of the pipe on the vessel. These clamping devices are operated by various combinations of linkages and hydraulic actuators which move the jaws in and out of clamping position.

One problem in providing quick disconnect couplers of the type described is that the standard flanged pipe is usually only machined on the end face and the outer edge. The back surface of the flange is generally not machined and therefore the thickness of the flange may vary considerably from pipe to pipe, and in fact the thickness of the flange may vary from point to point on a single flange. The clamping jaws cannot readily accommodate such variations in thickness of the flange. Accordingly it has been the practice to provide an adaptor which is secured to the pipe flange which is machined to close tolerances. The jaws of the coupler then engage the adaptor in clamping the coupler in place on the end of the pipe. However, the use of adaptors is undesirable for a number of reasons, such as the fact they are time consuming to install, they become damaged, lost, or misplaced, and they are a source of added expense. Various coupling designs have been proposed which provide individual adjustment of the jaws to accommodate variations in the thickness of the flange. For example, the jaws have been operated through spring linkage which allows the linkage to yield to variations in the position of the jaws when in the clamping position. Applying clamping pressure through springs, however, may result in insufficient clamping pressure resulting in poor sealing at the coupler. Cam-operated mechanisms have been proposed which provide positive clamping action. However, such systems have involved complex camming arrangements to get a combined radial movement for initially positioning the jaws and axial movement to apply clamping pressure against the back side of the flange.

The present invention is directed to an improved clamping mechanism for a quick disconnect coupler which is self-adjusting and provides a combined axial and radial movement of the clamping jaws. Thus the jaws provide a self-centering action in bringing the coupler and pipe into alignment for clamping them in a sealed connection. The clamping unit is hydraulically operated but does not rely on hydraulic pressure to maintain the jaws in the clamped position once the jaws are set. An overcenter toggle linkage provides a positive clamping action.

In brief, the present invention provides a quick disconnect coupler for connecting the flanged end of a pipe to a second pipe by means of a plurality of jaw actuator units. Each jaw actuator unit includes a support member anchored to one of the pipes. A frame member is movably supported on the support member for movement in a direction parallel to the axis of the pipe. A clamping jaw is movably supported from the frame member by a pair of linkage arms of different length. A pair of toggle arms are pivotally connected to each other and respectively to the frame member and to the jaw. An hydraulic actuator has one end connected to the pivotal connection between the two toggle arms. The other end of the hydraulic actuator is connected to a cam which is rotatably supported on the frame member. The cam has a cam surface in contact with a stop secured to the support member. The hydraulic actuator operates both the toggle linkage and rotates the cam to set the jaw in clamping position and to move the supporting frame axially to adjust for variations in thickness of the pipe flange.

For a better understanding of the invention reference should be made to the accompanying drawings, wherein:

FIG. 1 is a side view partly in section of the coupler mechanism in the closed or clamping position;

FIG. 2 is a partial side view in section showing the clamping mechanism in the open position; and

FIG. 3 is a partial end view of the coupler assembly.

Referring to the drawings in detail, the coupler assembly includes a section of pipe indicated generally at 10 which terminates at one end in a flange 12 by which the pipe section is mounted on the end of a standard pipe. The other end of the pipe section 10 is machined with lip 14 forming an end surface to which is attached a sealing gasket 16.

The quick disconnect coupler assembly includes a plurality of hydraulically operated clamping units, as indicated at 20, which are spaced circumferentially around the outer perimeter of the pipe section 10. Each of the clamping units, as hereinafter described in detail, operates a clamping jaw 22 which is designed to engage the flange 24 on the end of a standard pipe section 26 and clamp the face of the flange 24 against the sealing gasket 16 with the pipe 26 in axial alignment with the pipe section 10. The jaws 22 are formed with a notch 25 formed by facing material 27 for engaging both the outer perimeter and back surface of the flange 24. The hydraulic clamping units individually move the associated jaws between a clamping position, as shown in FIG. 1, and an open position, as shown in FIG. 2. The motion of the jaws is along an arc, indicated at 28, which is substantially perpendicular to the face of the flange at the clamping position and curves out and away from the flange in the open position, thus providing a substantially axial path of movement at the clamping position and a substantially radial movement as it approaches the open position.

Each clamping unit 20 is movably mounted on the pipe section 10 by a support member 30 which is in the form of a split collar, the two sections of the split collar being bolted together as indicated at 32 and 34. The split collar is thermally insulated from the pipe section by a pair of retaining rings 36 and 38 made of suitable thermal insulated plastic material. The retaining ring 36 engages the back of the lip 14 while the retaining ring 38 engages a shoulder 40 extending around the outside of the pipe section 10. The support member 30 is formed with peripheral flanges 42 and 44 which clamp the retaining rings in place. The space between the pipe section and the support member 30 is then preferably filled with a polyfoam insulating material 45 to isolate the supporting member 30 thermally from the pipe section 10 through which cryogenic liquids may be flowing.

The support member 30 has four pairs of grooved tracks, as indicated at 48, the tracks extending in a direction parallel to the axis of the pipe section. Each clamping unit includes a frame member, indicated generally at 50, having guides 52 which slidably engage the grooved tracks 48, thus allowing the clamping unit to be secured to the pipe section while allowing the clamping unit to be constrained to movement relative to the pipe section in a direction parallel to the axis of the pipe section.

Motion of the clamping unit 20 relative to the support member 30 is controlled by an hydraulic actuator 54. One end of the hydraulic actuator 54 terminates in a mounting arm 56. The mounting arm is pivotally connected to a pair of cams 58 which are rotatably supported on the frame member 50 by a shaft 60. The cams 58 have cam surfaces 64 which engage a pair of stops 66 projecting from the support member 30. The cams 64, as viewed in FIG. 1, are shaped such that clockwise rotation of the cams about the shaft 60 causes the distance between the axis of the shaft 60 and the stops 66 to increase, thereby forcing the clamping unit to shift to the left, as viewed in FIG. 1. The cams 58 may be held against the stops 66 by tension springs 70 secured at one end to the outer ends of the shaft 60 and at the other end to the support member 30.

The other end of the hydraulic actuator 54 is connected to an overcenter toggle linkage for moving the clamping jaw 22. The clamping jaw 22 is hinged to the frame member 50 by two pair of linkage arms 76 and 78. The linkage arms 76 are substantially longer than the linkage arms 78. When the clamping jaw 22 is in the clamped position shown in FIG. 1, the linkage arms 76 and 78 are substantially parallel and extend radially away from the axis of the pipe section. The linkage arms 76 and 78 are joined to the clamping jaw by hinge pins 80 and 82, respectively, which lie along a line extending substantially parallel to the axis of the pipe section when the jaw is in the clamping position. The other ends of the linkage arms 76 and 78 are connected to the frame member 50 by hinge pins 84 and 86, respectively.

In moving from the clamping position to the open position, the linkage arms 76 rotate about the hinge pin 84 and the linkage arms 78 rotate around the hinge pin 86. Since the arc through which the hinge pin 82 moves has a much shorter radius than the arc through which the hinge pin 80 is moved, rotation of the linkage arms 76 and 78 causes the notched end of the jaw to move initially laterally and then radially outwardly, in the manner shown in the drawings.

The jaw is moved between the clamping and open positions by the hydraulic actuator 54. To this end, the end of the hydraulic actuator is connected to the jaw by a pair of toggle arms 90 which are journaled at one end on the hinge pin 82 and journaled at the other end on a hinge pin 92 to which the end 88 of the actuator is connected. The end 88 of the actuator is also linked to the frame member 50 by a pair of toggle arms 94 which are hinged at one end on the hinge pin 84 and at the other end on the hinge pin 92.

In operation, if the length of the hydraulic actuator is expanded by admitting fluid under pressure to one end, it operates to open the jaw by causing the toggle linkage arms 94 to rotate about the hinge pin 84. This causes the toggle arms 90 to move the hinge pin 82 in a clockwise arc about the hinge pin 86, thereby causing the jaw to move from the clamped position to the open position. Because the hydraulic actuator is floating, that is, both ends are movable relative to the frame member 50, expansion of the hydraulic actuator also operates to rotate the cams 58 in a counterclockwise direction around the hinge pin or shaft 60. The cams are thus rotated by the expansion of the actuator 54 until the mounting arm 56 of the actuator moves to a detent position. In the detent position, a notch 100 in the end of the support arm 56 of the actuator engages a detent ball 102 which is part of a detent assembly 104 mounted on the frame member 50. The detent assembly 104 includes a compression spring which urges the detent ball 102 outwardly into engaging position with the notch 100.

With the jaws open and the cams in the detent position in which the clamping units are positioned in their most right-hand position, as viewed in FIG. 1, pipe coupling action is initiated by maneuvering the pipe section 10 into engagement with the flange 24. The open jaws 22, by means of guide surfaces 106, help to center the pipe section 10 in alignment with the flanged pipe 26. The hydraulic actuator 54 is then caused to retract, moving the end 88 of the actuator 54 to the left. The support arm 56 and associated cams 58 are held in detent position by engagement of the ball 102 in the notch 100. As a result, the jaws move radially inwardly into engagement with the back of the flange 24, the guide surfaces 106 acting to center and align the axis of the pipe section 10 with the pipe section 26. When the jaws are fully retracted into the clamping position, the pins 82, 84, and 92 are substantially aligned, with the pin 92 moving slightly past the centerline between the axis of the pins 82 and 84. In this position the toggle locks the jaw in the clamping position and the jaw cannot be opened unless the pin 92 is moved back over center by the hydraulic actuator 54. Once the toggle linkage is moved over center, further movement relative to the frame 50 is prevented by stops 110 on each end of the toggle pin 92 which come into engagement with the frame member at 112. Once the stops 110 engage the frame member 50, further retraction of the actuator 54 causes the cams 58 to rotate clockwise about the hinge pin 60. As a result the cam action against the stop 66 forces the frame member to the left, as viewed in FIG. 1, thereby moving the jaws axially into clamping engagement with the flange 24. Once in clamping position the hydraulic pressure in the actuator will build rapidly. This pressure can be sensed to stop additional flow of fluid to the actuator when a predetermined pressure level is reached. Even if the fluid pressure is then reduced to zero, full clamping pressure is retained at the jaws since over center toggle action and the rotation of the cams can only be overcome by a positive extension of the hydraulic actuator 54.